U.S. patent number 10,941,111 [Application Number 16/654,103] was granted by the patent office on 2021-03-09 for on-demand rapid synthesis of lomustine under continuous flow conditions.
This patent grant is currently assigned to Purdue Research Foundation. The grantee listed for this patent is Purdue Research Foundation. Invention is credited to Robert Graham Cooks, Christina Ramires Ferreira, Zinia Jaman, David H Thompson.
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United States Patent |
10,941,111 |
Thompson , et al. |
March 9, 2021 |
On-demand rapid synthesis of lomustine under continuous flow
conditions
Abstract
Disclosed herein is a continuous manufacturing process for
lomustine that has a short residence time and 63 percent yield.
Major advantages of this process are that the total production cost
for lomustine is lower, the product is higher quality, and the
manufacturing operation is safer for production personnel.
Inventors: |
Thompson; David H (West
Lafayette, IN), Cooks; Robert Graham (West Lafayette,
IN), Ferreira; Christina Ramires (West Lafayette, IN),
Jaman; Zinia (West Lafayette, IN) |
Applicant: |
Name |
City |
State |
Country |
Type |
Purdue Research Foundation |
West Lafayette |
IN |
US |
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Assignee: |
Purdue Research Foundation
(West Lafayette, IN)
|
Family
ID: |
1000005409054 |
Appl.
No.: |
16/654,103 |
Filed: |
October 16, 2019 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20200115330 A1 |
Apr 16, 2020 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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62746045 |
Oct 16, 2018 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C07C
273/1854 (20130101); C07C 273/1818 (20130101); B01J
19/0046 (20130101); C07C 273/1818 (20130101); C07C
275/26 (20130101); C07C 273/1854 (20130101); C07C
275/68 (20130101); C07C 275/68 (20130101); B01J
2219/00058 (20130101); B01J 2219/00033 (20130101); B01J
2219/00279 (20130101) |
Current International
Class: |
C07C
273/18 (20060101); B01J 19/00 (20060101); C07C
275/68 (20060101) |
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[Referenced By]
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|
Primary Examiner: Bonaparte; Amy C
Attorney, Agent or Firm: D'Hue Law LLC D'Hue; Cedric A.
Government Interests
GOVERNMENT SUPPORT
This invention was made with government support under CA023168
awarded by National Institutes of Health, and W911NF-16-2-0020
awarded by Army Research Laboratory. The government has certain
right in the invention.
Claims
The invention claimed is:
1. A method of producing Lomustine with a continuous flow
condition, wherein said Lomustine is prepared using starting
materials including cyclohexanamine, 1-chloro-2-isocyanatoethane,
triethylamine (TEA), and optionally a solvent via a linear sequence
of two chemical reactions performed separately in two telescoped
flow reactors, wherein an extractor is coupled with the first
telescoping reactor to remove excess starting materials from the
first reaction reactor, wherein the second chemical reaction
includes the step of nitrosation of an intermediate product, from
the first chemical reaction, 1-(2-chloroethyl)-3-cyclohexylurea,
using a nitrosation agent, wherein the nitrosation agent is sodium
nitrite in formic acid or tert-butyl nitrite.
2. The method of claim 1, further comprising screening the first
reaction conditions according to the method of claim 1:
##STR00005## in a continuous flow as a function of temperature,
solvent and stoichiometry, wherein the reaction is monitored by
thin-layer chromatography (TLC) and mass spectrometry (MS) using a
triple quadrupole mass spectrometer operating in positive ion mode
to identify an optimum reaction condition for the first
reaction.
3. The method of claim 1, comprising sequential)y: mixing cyclohex
anamine (1) and 1-chloro-2-isocyanatoethane (2) with triethylamine
(TEA) in the first telescoping reactor at 50.degree. C., for about
1 minute to form the first chemical reaction; wherein an
intermediate product 1-(2-chloroethyl)-3-cyclohexylurea (3) is
formed in the first chemical reaction; coupling the extractor with
the first telescoping reactor to remove excess base TEA from the
first chemical reaction; wherein the extractor is a liquid-liquid
extractor; transferring the intermediate product
1-(2-chloroethyl)-3-cyclohexylurea (3) from the first telescoping
reactor to the second telescoping reactor in a continuous flow; and
carrying out nitrosation of the intermediate product
1-(2-chloroethyl)-3-cyclohexylurea (3) in the second telescoping
reactor at 25.degree. C. for about 8 minutes using tort-butyl
nitrite (tBuONO (5) as the nitrosation agent to form the second
chemical reaction; wherein the final product Lomustine is formed in
the second chemical reaction.
4. The method of claim 1, wherein the first chemical reaction is
performed at a temperature within the range of about 25.degree. C.
to about 65.degree. C.
5. The method of claim 1, wherein the first chemical reaction is
performed at a temperature selected from the group consisting of
room temperature, about 25.degree. C., about 50.degree. C., and
about 65.degree. C.
6. The method of claim 1, wherein the first chemical reaction is
perfomed for a residence time within the range of about 10 seconds
to about three minutes.
7. The method of claim 1, wherein the first chemical reaction is.
performed for a residence time selected from the group consisting
of about 10 seconds, about 30 seconds, about 60 seconds, and about
180 seconds.
8. The method of claim 1, wherein the extractor is coupled with the
first telescoping, reactor to remove excess triethylamine (TEA)
from the first reaction.
9. The method of claim 8, wherein the extractor is a liquid-liquid
extractor.
10. The method of claim 1, wherein the nitrosation is carried out
at a temperature of about 0.degree. C. when sodium nitrite in
formic acid is used as the nitrosation agent or about 25.degree. C.
to about 50.degree. C. when tent-butyl nitrite is used as the
nitrosation agent.
11. The method of claim 1, wherein the second chemical reaction is
performed in a solvent Selected from the pup consisting of dimethyl
sulfoxide (DMSO), toluene, acetonitrile (ACN), dichloromethane
(DCM), ethanol (EtOH), and methanol (MeOH).
12. The method of claim 1, wherein the second chemical reaction is
performed for a residence time within the range of about 30 seconds
to about ten minutes.
13. The method of claim 1, wherein the nitrosation agent is sodium
nitrite in formic acid.
14. The method of claim 1, wherein the nitrosation agent is
tert-butyl nitrite.
15. The method of claim 13, wherein the second chemical reaction is
performed in a solvent selected from the group consisting of ethyl
acetate (EtOAc), tetrahydrofuran (THF), dimethyl sulfoxide (DMSO),
toluene, acetonitrile (ACN), dichloromethane (DCM), ethanol (DOH),
methanol (MeOH), and methanol:water (4:1 v/v).
16. The method of claim 14, wherein the second chemical reaction is
performed in a solvent selected from the group consisting of
dimethyl sulfoxide (DMSO), toluene, acetonitrile (ACN),
dichloromethane (DCM), ethanol (EtOH), methanol (MeOH), and
acetonitrile:ethanol (3.7:1 v/v).
17. The method of claim 13, wherein the second chemical reaction is
performed at 0.degree. C.
18. The method of claim 1, wherein the two chemical reactions do
not include a purification step of a reaction intermediate.
19. The method of claim 1. wherein the first chemical reaction is
performed in a solvent selected from the group consisting of
ethanol (Et0H). acetonitrile (CCN), Toluene, Ether and
tetrahydrofuran (THF).
20. The method of claim 14, wherein the second chemical reaction is
performed at a temperature within the range of about 25.degree. C.
to about 50.degree. C.
Description
FIELD OF INVENTION
This disclosure provides a novel method of synthesizing lomustine
drug in scalable size under continuous flow conditions.
Particularly, lomustine is prepared via a linear sequence of two
chemical reactions performed separately in two telescoped flow
reactors. The process omits isolation and purification of a labile
intermediate, providing tremendous advantages of producing active
pharmaceutical ingredient at low cost.
BACKGROUND
Lomustine, a widely used anticancer agent, is a highly lipophilic
alkylating agent that produces chloroethyl carbonium ions and
carbamylating intermediates in vivo..sup.[1] These electrophilic
compounds attack the nucleophilic sites on DNA to form alkylated
products..sup.[1a] Other anticancer agents such as mitomycin C,
streptonigrin, bleomycin, and the anthracyclines require
bioactivation to react with their cellular targets, whereas
lomustine does not require pre-activation..sup.[2] Unlike
alkylating agents that form adducts at the most reactive N.sup.7
position of guanine, chloroethylating compounds like lomustine form
adducts at O.sup.6, leading to interstrand DNA cross-linking. If
DNA repair does not occur, this crosslinking can cause double
strand breaks during DNA replication, eventually leading to cell
death via apoptosis..sup.[3]
Lomustine, 1-(2-chloroethyl)-3-cyclohexyl-1-nitroso-urea
(commercial names: CCNU, CeeNU, Gleostine) is used as an oral
antineoplastic agent that is administered every 6 weeks. It was
first evaluated in clinical trials in the late 1960s.sup.[4] and
approved by the US FDA in 1976.sup.[5] for primary and metastatic
brain tumors as well as Hodgkin's lymphoma..sup.[3] Bristol-Myers
Squibb originally held the patent for the agent under the brand
name CeeNu. In 2014, Next Source Biotechnology LLC (NSB) was
approved by the FDA for the rebranding of lomustine under the trade
name Gleostine..sup.[5] The average wholesale price for one dose of
rebranded Gleostine is $1,645.68, while the generic formulation
costs $203.38..sup.[5] The huge price discrepancy (700%) between
Gleostine and the generic formulation has created patient access
problems, thus motivating our effort to develop a rapid and low
cost lomustine synthesis method by continuous flow.
Continuous flow synthesis has been reported as an efficient
methodology and has been explored in both industry and academic
labs for the last few decades:.sup.[6] Compared to traditional
batch synthesis processes, flow reactors provide better control
over reaction conditions and selectivity owing to rapid mixing and
precise control of reaction parameters such as temperature,
stoichiometry, pressure, and residence time. The enhanced heat and
mass transfer capabilities also provide safer and greener
operational conditions:.sup.[6b, 7] Generally, these aspects of
continuous flow synthesis contribute to improved chemical reaction
efficiency.sup.[7g, 8] and shorter reaction times, enabling process
intensification.sup.[7a], and more facile scale-up, with improved
quality and consistency in production. Motivated by these factors,
continuous flow synthesis of active pharmaceutical ingredient has
recently become more attractive,.sup.[7g, 9] however efficient
execution of multistep reactions in a telescoped manner still
remains a challenge due to challenges arising from workup
conditions.sup.[9f, 10], solvent switches,.sup.[11] and flow rate
differences..sup.[11a, 12] Moreover, optimization of continuous
flow conditions and analysis require significant investments in
time and material..sup.[9f, 13]
SUMMARY OF THE INVENTION
This disclosure provides a method of producing Lomustine with
continuous flow condition, the method comprises the steps
illustrated in FIG. 6, or steps illustrated in FIG. 20.
This disclosure further provides a method of identifying optimum
reaction condition of producing Lomustine. The method comprises
screening the reaction condition according to scheme 1 in a
continuous flow as a function of temperature, solvent and
stoichiometry, wherein the reaction is monitored by TLC and MS
using a triple quadrupole mass spectrometer operating in positive
ion mode to afford rapid investigation of full mass spectra and
product ion distribution for each reaction condition.
This disclosure further provides a system for telescoped Lomustine
synthesis. The system comprises sequentially: a first telescoping
chamber mixing cyclohexylamine (1) and 1-chloro-2-isocyanatoethane
(2) with triethyalamine (TEA) at 50 C for about 1 minute; a Zaiput
liquid-liquid extractor to couple with the first telescoping
chamber to remove the base TEA from the first reaction chamber; and
a second telescoping chamber for nitrosation of the intermediate
product 1-(2-chloroethyl) -3-cyclohexylurea (3) at 25 C for about 8
minutes using tBuONO (5) as the nitrosation agent.
These and other features, aspects and advantages of the present
invention will become better understood with reference to the
following figures, associated descriptions and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1: Microfluidic synthesis of intermediate 3 in a glass reactor
chip (SOR 3225). A=1 in THF; B=2 in THF, C=TEA in THF.
FIG. 2: DESI-MS plate maps showing the presence or absence of
expected ions at each spot where the nitrosation reaction
conditions were tested using different stoichiometries and with
commercially available standards. Blue dots indicate the presence
of the m/z 169 expected stable fragment for the reaction product
(successful reaction), Red dots indicate that the expected m/z for
the reaction product was not present at the reaction spot
(unsuccessful reaction condition). A: Concentration screening using
the lomustine ion (m/z 169) intensity and NaNO.sub.2 as nitrosation
reagent; B: Solvent screening using the lomustine ion (m/z 169)
intensity and NaNO.sub.2 as nitrosation reagent; C: Solvent
screening using the lomustine ion (m/z 169) intensity and tBuONO as
nitrosation reagent.
FIG. 3: Microfluidic synthesis of lomustine using
NaNO.sub.2/HCO.sub.2H as nitrosation reagent in a Chemtrix 3225 SOR
glass reactor chip. A=3 in THF; B=HCO.sub.2H (neat), C=NaNO.sub.2
in MeOH:H.sub.2O (4:1).
FIG. 4: Microfluidic synthesis of lomustine using 5 as nitrosation
reagent in a Chemtrix 3223 SOR glass reactor chip. A=3 in ACN:EtOH
(3.7:1) ; B=5 in ACN.
FIG. 5: Schematic for the telescoped synthesis of lomustine using
NaNO.sub.2/HCO.sub.2H (4) as nitrosation reagent.
FIG. 6: Schematic for the final telescoped synthesis of lomustine
using 5 as a nitrosation reagent.
FIG. 7: Total ion chromatogram (TIC) from HPLC-MS/MS and comparison
between synthesized lomustine (top, red) and commercially available
lomustine (bottom, black).
FIG. 8A and FIG. 8B: Full ESI-MS scan and MS/MS of commercially
available 3 and synthesized 3 derived from flow under the reaction
conditions of 50.degree. C., 1 min.
FIG. 9: DESI master plate layout using four different
concentrations in two solvents.
FIG. 10: DESI master plate layout using eight different
solvents.
FIG. 11: DESI master plate layout using only commercially available
3 and lomustine.
FIG. 12: (left) Direct DESI-MS data comparison between the two
nitrosation reactions in THF and ACN in different concentration.
(right) DESI-MS data of commercially available 3 and lomustine
standards. The data was analyzed using BioMAP imaging software.
FIG. 13: (left & center) Direct DESI-MS data comparison between
the two nitrosation reactions in different solvents. (right)
DESI-MS data of commercially available 3 and lomustine standards.
The data was analyzed using BioMAP imaging software.
FIG. 14A to FIG. 14C: Map of the DESI-MS plates showing some of the
expected ions where the nitrosation reaction was screened using
different stoichiometries as well as commercially available
standards. Green dots indicate the presence of the m/z expected for
the reaction product (successful reaction), Red dots indicate that
the expected m/z for the reaction product was not present at the
reaction spot (unsuccessful reaction condition). A: NaNO.sub.2,
concentration screening using the lomustine ion (m/z 169)
intensity; B: NaNO.sub.2, solvent screening using the lomustine ion
(m/z 169) intensity; C: TBN, solvent screening using the lomustine
ion (m/z 169) intensity
FIG. 15: Comparison of .sup.1H NMR of lomustine synthesized by
continuous flow for different methods of purification.
FIG. 16: Full MS scan and MS/MS of m/z=169 from commercially
available lomustine and synthesized lomustine form flow. Reaction
conditions were 25.degree. C., 8 min.
FIG. 17: Telescoped two step synthesis of lomustine using sodium
nitrite in the second step.
FIG. 18: First step of the telescoped synthesis of lomustine.
FIG. 19: Second step of the telescoped synthesis of lomustine using
NaNO.sub.2 as a nitrosation reagent.
FIG. 20: Telescoped lomustine synthesis using TBN as a nitrosation
reagent, before reaction initiation.
FIG. 21: Telescoped lomustine synthesis using TBN (protected from
light).
FIG. 22: Second step of the telescoped synthesis of lomustine using
TBN.
FIG. 23: TLC monitoring during lomustine synthesis in flow
FIG. 24: Comparison of TLC of telescoped lomustine synthesis using
different equivalents of base
DETAILED DESCRIPTION
While the concepts of the present disclosure are illustrated and
described in detail in the figures and the description herein,
results in the figures and their description are to be considered
as exemplary and not restrictive in character; it being understood
that only the illustrative embodiments are shown and described and
that all changes and modifications that come within the spirit of
the disclosure are desired to be protected.
Unless defined otherwise, the scientific and technology
nomenclatures have the same meaning as commonly understood by a
person in the ordinary skill in the art pertaining to this
disclosure.
Lomustine, an important agent for treatment of brain tumors and
Hodgkin's lymphoma, has been synthesized using continuous flow
methodology. Desorption electrospray ionization mass spectrometry
(DESI-MS) was used to quickly explore a large number of reaction
conditions and guide the efficient translation of optimized
conditions to continuous lomustine production at a rate of
approximately one dose/h. Using only four inexpensive commercially
available starting materials and a total residence time of 9 min,
lomustine was prepared via a linear sequence of two chemical
reactions performed separately in two telescoped flow reactors.
Sequential offline extraction and filtration resulted in 63%
overall yield of pure lomustine at a production rate of 110 mg/h.
The primary advantage of this approach lies in the rapid
manufacture of lomustine with two telescoped steps to avoid
isolation and purification of a labile intermediate, thereby
decreasing the production cost of this active pharmaceutical
ingredient to approximately $5/gram in total material cost.
Briefly, herein we disclose robust high throughput reaction
screening method using desorption electrospray ionization mass
spectrometry (DESI-MS) to guide scalable synthesis in continuous
flow reactors at scale..sup.[13e] Herein, we report the continuous
flow synthesis of lomustine using an optimization protocol that was
guided by DESI-MS. The final method consists of two reactions
telescoped without isolation or purification of intermediates. This
approach can reduce production costs radically by using a simple
reactor set up and inexpensive starting materials (Scheme 1). To
the best of our knowledge, this is the first synthesis of lomustine
telescoped in continuous flow using an approach that does not
interrupt the flow sequence due to intermediate workup
requirements.
##STR00001##
Continuous Synthesis of 1-(2-Chloroethyl)-3-cyclohexylurea, 3.
The first step in the synthesis of lomustine (Scheme 1) is a fast
reaction at room temperature. This transformation was optimized in
continuous flow as a function of temperature, solvent, and
stoichiometry to discover the conditions for maximum product yield.
The reactions were monitored by TLC and MS using a triple
quadrupole mass spectrometer operating in positive ion mode to
afford rapid investigation of full mass spectra and product ion
distribution for each reaction condition.
TABLE-US-00001 TABLE 1 Reaction conditions evaluated for the
synthesis of 3 in flow using a Chemtrix S1 glass system fitted with
a 3225 SOR reactor chip. 2 Temperature, Residence Isolated Entry
Solvent equivalent .degree. C. time, sec Yield % 1 EtOH 1 50 10
42.8 2 EtOH 1 50 30 0.00 3 EtOH 1 50 60 0.00 4 ACN 1 50 10 56.2 5
ACN 1 50 30 clogged 6 ACN 1 25 30 clogged 7 Toluene 1 50 10 clogged
8 Ether 1 50 10 clogged 9 THF 1 25 10 50.0 10 THF 1 25 30 56.4 11
THF 1 50 10 59.5 12 THF 1 50 30 62.1 13 THF 1 65 10 47.5 14 THF 1
65 30 29.1 15 THF 1.2 50 10 61.2 16 THF 1.2 50 30 64.8 17 THF 1.2
50 60 71.3 18 THF 1.4 50 10 67.1 19 THF 1.4 50 30 82.0 20 THF 1.4
50 60 91.7 21 THF 1.4 50 180 82.8
A cascade method was designed to reveal the best conditions for the
first step. Cyclohexylamine, 1, 1-chloro-2-isocyanatoethane, 2, and
triethylamine (TEA) solutions were pumped through a Chemtrix 3225
SOR chip with automatic collection of the products in vials via an
autosampler (FIG. 1). The individual reaction mixtures were
evaporated and the white solid washed with cold Et.sub.2O before
drying under vacuum for overnight prior to analysis by TLC, MS,
MS/MS, and NMR (.sup.1H and .sup.13C).
Parameters such as residence time (t), reaction temperature (T),
1-chloro-2-isocyanatoethane:cyclohexylamine ratio were investigated
systematically under continuous flow conditions. As shown in Table
1, product yield dropped sharply in EtOH at longer residence times
(entries 1-3) due to ethanolysis of the
1-chloro-2-isocyanato-ethane starting material. Though the yield of
3 in ACN was significant, its low solubility in this solvent led to
significant chip clogging (entries 4-6). Similar clogging problems
were found for toluene and Et.sub.2O, even at low concentrations
(entries 7-8). The yield increased to 50-62% with longer residence
times (entries 9-14) in THF, reaching a maximum when .tau.=30 s at
50.degree. C. and decayed rapidly with increased temperature
(entries 13, 14) due to increased product decomposition at elevated
temperature. The yield of 3 was also found to increase with
proportions of 2 ratio (entries 15-21), whereas longer residence
times promoted product decomposition (entry 21). Consequently, a
maximum yield of intermediate 3 (92%) was achieved under conditions
of .tau.=60 s, T=50.degree. C., and 1.4 equivalents of
1-chloro-2-isocyanatoethane (entry 20).
Synthesis of Lomustine, Guided by DESI-MS High Throughput
Experimentation.
We employed DESI-MS to evaluate the impact of solvent,
concentration and nitrosation reagent type on the efficiency of
lomustine production. DESI-MS was originally applied to the surface
analysis of intact samples such as biological tissues for cancer
diagnosis or human fingerprints for drug detection,.sup.[14]
although more recently, the DESI-MS approach has been used for
reaction analysis..sup.[13e] This approach is based on the
phenomena of reaction acceleration that occurs within confined
volumes such as microdroplets that originate from spray-based MS
ionization processes..sup.[14a] MS analysis speeds approaching
10,000 reaction spots/hour can be achieved by this
technique..sup.[13e]
As shown in Scheme 1 (2.sup.nd step), two nitrosation methods were
investigated. First, the efficiency of sodium nitrite, 4, in formic
acid as the nitrosation reagent toward the conversion of 3 to
lomustine was evaluated. This conversion was then compared with
tert-butyl nitrite (TBN, 5) as the nitrosation reagent.
DESI-MS was used to evaluate the NaNO.sub.2/HCO.sub.2H
transformation under different reactant concentrations and
solvents. The expected m/z 234 value for lomustine were not
observed. Analysis of a commercial lomustine sample yielded a very
similar MS, suggesting that loss of NO occurs readily during the
ionization process. Triple quadrupole MS with electrospray
ionization, as well as ion trap mass spectrometry coupled with
DESI, revealed the presence of a stable lomustine ion at m/z 169.
This was further confirmed by the fact that the losmustine
fragments from this reaction matched with commercially available
lomustine. Reactions for all NaNO.sub.2 concentrations in
THF:H.sub.2O worked better than for ACN:H.sub.2O (FIG. 2, A). Also,
the fragments from 3 were most abundant in the ACN:H.sub.2O
reactions compared to reactions in THF:H.sub.2O, suggesting that
the conversion of starting material was comparatively sluggish in
ACN:H.sub.2O. Next, eight different solvents (EtOH, MeOH, DCM, ACN,
toluene, DMSO, THF and EtOAc) were compared for guiding the
continuous flow synthesis. All eight solvents produced similar
outcomes using 4 as the nitrosation reagent (FIG. 2, B). When 5 was
used, lomustine was detected in all solvents except THF and EtOAc
(FIG. 2, C).
Nitrosation Reaction Optimization in Continuous Flow.
We utilized the reaction conditions emerging from the DESI-MS high
throughput experiments to optimize the flow synthesis and also
check whether unsuccessful reactions identified by DESI-MS would
also negatively translate under flow conditions. From the DESI-MS
experiments, THF was identified as the best solvent for nitrosation
using 4. Excess 4 was also used to maximize conversion of 3 to
lomustine since the nitrosation reagents are hygroscopic and
readily oxidize to nitrate..sup.[15] Overall, the DESI-MS
experiments were in excellent agreement with the outcomes of flow
reaction conditions in terms of stoichiometry, reagents and
solvents.
A series of reactions (Table 2) were performed to maximize the
conversion of 3 to lomustine under continuous synthesis conditions
(FIG. 3). Initially, we examined the reaction at 0.degree. C. with
a residence time of 30 sec using TLC and MS to monitor the reaction
progress. Gratifyingly, lomustine was obtained through this very
short reaction time, albeit in low conversion (Table 2, entry 1). A
systematic evaluation of residence times led to good lomustine
yields and starting material conversions, however, longer residence
times appeared enhance the decomposition of lomustine (Table 2,
entries 2-6). Consequently, we kept the temperature constant at
0.degree. C. to avoid NaNO.sub.2 decomposition of sodium nitrite to
the diazonium salt that occurs at higher
temperatures..sup.[15b]
Different purification methods were evaluated to isolate pure
lomustine. At first, the product was extracted with Et.sub.2O (3
times) to exploit the low solubility of 3 in this solvent (Method
1). Unfortunately, the TLC analysis revealed the presence of 3 in
the organic layer as well as in the aqueous layer. Therefore, the
combined organic extracts were dried over anhydrous
Na.sub.2SO.sub.4 and concentrated in vacuo to produce a yellowish
oil that re-dissolved in Et.sub.2O, heated and cooled in an ice
bath to precipitate 3 from the mixture. NMR analysis of the
filtrate revealed that 22% of 3 remained in the isolated lomustine
product. Next, we purified the product by recrystallization from
ACN (Method 2). Although we obtained very pure lomustine as
identified by NMR analysis, recovery using this approach was low.
Finally, we found that hot filtration from petroleum ether removed
the insoluble 3 impurity (Method 3). Concentration of the filtrate
after drying gave pure lomustine without detectable amount of 3 by
NMR. Using this method, we obtained 74% isolated yield of pure
lomustine under the conditions of 0.degree. C. reaction and a
residence time of 5 min using 3 equivalents of 4.
TABLE-US-00002 TABLE 2 Isolated yields of lomustine under different
reaction conditions using 4 as the nitrosation reagent. Temperture
= 0.degree. C., solvent = MeOH:H.sub.2O (4:1) Residence Isolated
Yield Isolated Yield Isolated Yield Entry time, min (Method 1) %
(Method 2) % (Method 3) % 1 0.5 26.8 -- 43.7 2 1 48.8 -- 50.6 3 3
51.6 41.2 63.1 4 5 79.0 54.4 74.5 5 8 59.0 -- 68.7 6 10 50.2 --
65.3
The reaction was also optimized with respect to residence time,
temperature, and solvent using 5 as nitrosation agent (FIG. 4 and
Table 3). This optimization process led to the finding that an
elevated residence time (8 min), lower temperature (25.degree. C.)
and increased 5 ratio (3 equiv) resulted in the most efficient
conversion to lomustine (91% isolated yield) after Method 3
purification (Table 3, entry 11).
TABLE-US-00003 TABLE 3 Synthesis of lomustine under at different
reaction conditions using 5 as the nitrosation reagent. Isolated
Temperature, Residence Lomustine Entry Solvent (3.7:1) (.degree.
C.) time, (min) Yield (%) 1 ACN:EtOH 50 0.5 68.3 2 ACN:EtOH 50 1
69.8 3 ACN:EtOH 50 3 60.0 4 ACN:EtOH 50 5 58.8 5 ACN:EtOH 50 8 51.9
6 ACN:EtOH 50 10 49.4 7 ACN:EtOH 25 0.5 48.8 8 ACN:EtOH 25 1 54.1 9
ACN:EtOH 25 3 66.5 10 ACN:EtOH 25 5 79.3 11 ACN:EtOH 25 8 91.2 12
ACN:EtOH 25 10 89.8 13 THF(100%) 25 3 36.5
Telescoped Synthesis of Lomustine
The next step was to adapt the whole two step sequence to a
continuous flow setup. We sought to telescope the carbamylation and
nitrosation reactions using the Chemtrix reactor chips, however, an
extraction needed to be incorporated between the steps to remove
the TEA present in the first reaction to avoid competitive
consumption of the nitrosation reagent in the second step. We
achieved this objective by incorporating a commercially available
Zaiput liquid-liquid extractor to remove the base before the
nitrosation step and by re-optimizing the synthesis using FEP
tubing reactors (FIG. 5). In the beginning, the best reaction
conditions were a 1 min residence time at 50.degree. C. for the
first step and a 5 min residence time at 0.degree. C. for the
second step, yielding 43 mg (51.8% overall yield) of pure lomustine
(Table 4, entry 1). Efforts to improve the lomustine yield by
changing the residence times of either the first or second steps
were unsuccessful in the FEP tubing reactor using 4 as nitrosation
reagent (Table 4, entry 1-4).
TABLE-US-00004 TABLE 4 Lomustine synthesis yields for telescoped
reactions under different eagents, residence time, stoichiometry,
and temperature conditions. Isolated Nitrosation TEA Lomustine
Entry reagent Step 1 Step 2 Stoichiometry Yield % 1 4 1 min,
50.degree. C. 5 min, 0.degree. C. 1 51.8 2 4 2 min, 50.degree. C. 5
min, 0.degree. C. 1 44.2 3 4 10 min, 50.degree. C. 5 min, 0.degree.
C. 1 38.6 4 4 10 min, 50.degree. C. 3 min, 0.degree. C. 1 24.0 5 5
1 min, 50.degree. C. 5 min, 50.degree. C. 1 41.5 6 5 1 min,
50.degree. C. 5 min, 25.degree. C. 1 21.8 7 5 1 min, 50.degree. C.
8 min, 25.degree. C. 1 24.6 8 5 1 min, 50.degree. C. 8 min,
25.degree. C. 0.1 55.5 9 5 1 min, 50.degree. C. 8 min, 25.degree.
C. 0.01 63.7
Subsequent telescoping experiments indicated that 5 was a better
nitrosation reagent than 4 for the efficient synthesis of lomustine
in flow. This is also true when the synthesis of lomustine were
performed separately in glass reactor chips (Table 2 and 3). The
final optimized conditions were 1 min reaction time at 50.degree.
C. for the first step and 8 min reaction time at 25.degree. C. for
the second step (FIG. 6). As the small amount of extracted TEA from
the first step minimized the TBN activity, lowering the amount of
TEA used led to an increased production of lomustine (Table 4,
entries 7-9) such that 1% TEA produced 110 mg (63%) of pure isolate
lomustine via this reaction setup (Table 4, entry 9). TLC, NMR
(.sup.1H and .sup.13C), MS and MS/MS data of lomustine obtained by
this telescoped continuous route were a direct match with values
measured for commercially available lomustine.
HPLC-MS was used to certify the purity of the synthesized lomustine
and compare the total ion chromatogram (TIC) values of this
material with a commercial lomustine standard. The TIC profile
fully overlapped with the commercial standard without the
appearance of any new byproducts (FIG. 7).
We have developed a rapid continuous synthesis of lomustine using
DESI-MS to guide the selection of reaction conditions in the second
step of the two step overall transformation. The total residence
time is 9 minutes to produce pure lomustine in 63% overall isolated
yield compared to over 2 hours to generate a lower product yield
using batch conditions..sup.[1b, 2, 16] The two synthetic steps
were optimized separately in glass chips and then translated to FEP
tubing for telescoped scaling of the whole process. Only one
in-line workup step was required for the two-step reaction
sequence. Mixed solvents were used in the telescoped reaction to
avoid clogging due to the low solubility of 3. tButyl nitrite, 5,
was found to be a milder and more efficient nitrosation reagent in
this process to enable the isolation of pure lomustine via simple
extraction, filtration and washing. This synthesis is a faster and
greener process that affords a significant reduction in reaction
time, lower waste production, and avoidance of any chromatographic
steps. Using this method, 110 mg/hour of lomustine can be produced,
equivalent to one dose/h for an agent that is administered orally
every 6 weeks. Scale up and in-line recrystallization of lomustine
are in progress.
Supporting Information
Materials
All chemicals and reagents were purchased from Sigma-Aldrich (St
Louis, Mo.) and used without any purification. Intermediate 3
standard was purchased from 1Click Chemistry, Inc. (Kendall Park,
N.J.). Lomustine was purchased from ApexBio (Houston, Tex.).
Liquid Handling Robot
Assay plate set up and sample preparation steps for DESI-MS were
done using a Biomek i7 (Beckman Coulter, Inc., Indianapolis, Ind.)
dual-bridge liquid handling robot. A 384-tip head was employed to
enable simultaneous transfer of 384 samples under the same
conditions (speed of aspiration and dispensing, height of pipetting
at source and destination positions, pattern of pipetting, etc.).
An 8-channel head was used to provide more flexibility in terms of
volumes transferred, layout of source and destination places,
pipetting height, speed, and reaction stoichiometry. The high
capacity deck accommodated all labware (robotic tips, plates,
reservoirs) needed for assembling one reaction step. All robotic
tips were made of chemically resistant polypropylene and
disposable. Polypropylene multi-well plates and reservoirs, as well
as custom made Teflon reservoirs were used during the experiments
for reagent solutions. Methods were developed and validated using
the Biomek point-and-click programming tool. Standard pipetting
techniques used in this software were modified to optimize accurate
transfer of highly volatile liquids.
Mass Spectrometry
Samples were analyzed using a Thermo Fisher TSQ Quantum Access MAX
mass spectrometer that was connected with a Dionex Ultimate 3000
Series Pump and WPS-3000 Autosampler (Thermo Fisher Scientific,
Waltham, MA). Electrospray ionization (ESI) analysis in full scan
mode was used to monitor each reaction in both positive and
negative ion modes. These data were recorded using optimized
parameters for the ESI source and MS as follows: spraying solvent,
ACN; spray voltage +3.5 kV (positive mode) and -4.0 kV (negative
mode); capillary temperature, 250.degree. C.; Sheath gas pressure,
10 psi; scan time, 1 s; Q1 peak width (FWHM), 0.70 Th; micro scans,
3. The autosampler settings were as follows: MS acquire time, 2
min; sample injection volume, 10 .mu.L. Thermo Fisher Xcalibur
software was used to process the data from the MS spectrometer.
NMR Analysis
.sup.1H-NMR and .sup.13C-NMR were acquired using a Bruker
AV-III-500-HD NMR spectrometer (Billerica, Mass., USA). Samples for
NMR were prepared by dissolving .about.5 mg of sample in
CDCl.sub.3. MestReNova 10.0 software was used to analyze the
.sup.1H-NMR and .sup.13C-NMR.
Chemtrix S1 Microfluidics System.
The two step synthesis of lomustine was performed using a Labtrix
51 microfluidic reactor system (Chemtrix, Ltd, Netherlands). The
reactor parts are made of PPS (polyphenylsulfide) and
perfluoroelastomer to provide excellent chemical resistance. The
system has a temperature range for synthesis from -20.degree. C. to
+195.degree. C. and pressures of up to 35 bar. The outer diameter
of the fluorinated ethylene propylene (FEP) tube is 1/32 inches and
the inner diameter is 150 .mu.L. The 3223 and 3225 microreactors
are made of glass and were used for all conducted reactions. The
staggered orientated microreactor (SOR) chip 3223 (three inlets and
one outlet, volume 10 .mu.L) and 3225 (four inlets and one outlet,
volume 10 .mu.L) have a channel width of 300 .mu.m and a channel
depth of 120 .mu.m. The Labtrix unit is able to independently pump
five syringes into the microreactor seated on a Peltier heating and
cooling unit. All the gastight glass syringes were bought
separately from Hamilton Company (Hamilton, Reno, Nev.). The tubing
and fittings connect the syringes with the selected connection port
on the microreactor. All operations were controlled using a
Chemtrix GUI software installed on a laptop that was connected to
the Labtrix S1 casing with a USB cable.
Liquid-Liquid Separator.
All the liquid-liquid separations were performed using a SEP-10
unit (Zaiput Flow Technologies, Cambridge, Mass.). The separator
uses a porous hydrophobic PTFE membrane (OB-900) which allows flow
of the organic phase through the membrane. The organic phase wets
the membrane while the aqueous phase does not. A built-in pressure
controller is used to maintain the appropriate pressure
differential that is required of the flow for both sides of the
membrane.
DESI-MS Analysis
The DESI-MS evaluation was done following the previously published
method of Wleklinski et al.sup.[1] except that the density of
reaction spots was 1536 spots/plate instead of 6144/plate using
reagents that were pipetted into standard polypropylene 384-well
plates using a liquid handling robot (Biomek i7; Beckman-Coulter,
US). DESI-MS slides were fabricated from porous PTFE sheets (EMD,
Millipore Fluoropore, Saint-Gobain) glued onto a glass support
(Foxx Life Sciences). The PTFE sheet was cut with scissors and
bonded to the glass slides using spray adhesive (Scotch Spray
mount). No signs of interference from the glue was observed. The
reagents were mixed at 1:1 stoichiometry in various solvents
(EtOAc, THF, DMSO, Toluene, ACN, DCM, EtOH and MeOH) and rhodamine
B dye was added to some wells of the plate as a fiducial marker.
After the reagents were mixed, 50 nL of the reactions were
deposited onto a porous PTFE surface at 1,536 spot density using a
magnetic pin tool equipped with slotted transfer pins. DESI-MS data
was acquired using a linear ion trap mass spectrometer (LTQ XL;
Thermo Scientific, San Jose, Calif.) equipped with a commercial
DESI-imaging source (DESI 2D source, Prosolia Inc., Indianapolis,
Ind.). The instrument was controlled using Xcalibur v. 4.0 software
to run worklists for DESI-MS data acquisition. The DESI spray angle
was 55.degree. using MeOH as spray solvent, and with an applied
voltage of 5 kV. Mass spectra were acquired at the positive ion
mode over the m/z range of 50-500. The DESI-MS imaging lateral
resolution was 350 .mu.m. This was achieved using stage speed of
4,376 .mu.m/sec and the instrument scan time of 80 ms. For data
processing, data were visualized using an in-house software
designed.sup.[1] to automatically search for the m/z values of
reactants, intermediates, and lomustine fragments to generate a
YES/NO visualization output for each spot in the PTFE plate imaged
by DESI-MS. Data files also were combined into .img files using
Firefly software (Prosolia Inc., Indianapolis, Ind.). Ion images
were plotted using BioMAP (Novartis, freeware). The expected m/z
values for the lomustine fragments were plotted and visualized
using the BioMAP rainbow false color scale where the minimum and
maximum ion intensity values were set to the best contrast for each
ion.
HPLC-MS Analysis
HPLC/MS analysis was performed using an Agilent 6545
UPLC/quadrupole time-of-flight (Q-TOF) mass spectrometer (Palo
Alto, Calif.), with an Agilent XDB-C18 column (3.5 .mu.m,
150.times.2.1 mm i.d.) and 5 .mu.L injection volume. A binary
mobile phase, consisting of solvent systems A and B was used. A was
0.1% formic acid (v/v) in ddH.sub.2O and B was 0.1% formic acid
(v/v) in ACN. Isocratic elution of A:B at 95:5 was used, with a
column flow rate of 0.3 mL/min. Following the separation, the
column effluent was introduced by positive mode electrospray
ionization (ESI) into the mass spectrometer. High mass accuracy
spectra were collected between 70-1000 m/z. Mass accuracy was
improved by continuously infusing Agilent Reference Mass Correction
Solution (G1969-85001). The MS detection conditions were: ESI
capillary voltage, 3.5 kV; nebulizer gas pressure, 30 psig; gas
temperature, 325.degree. C.; drying gas flow rate, 8.0 L/min;
fragmentor voltage, 130 V; skimmer, 45 V; and OCT RF V, 750 V.
Carbamylation of Cyclohexylamine
Experimentation.
A solution of cyclohexylamine (1, 500 mmol, 1 equiv) in THF was
loaded into 1 mL Hamilton gas tight glass syringe. Triethylamine
(TEA) (500 mmol, 1 equiv) and 1-chloro-2-isocyanatoethane (2, 700
mmol, 1.4 equiv) solutions in THF were individually loaded into
another two 1 mL Hamilton gas tight glass syringes. Each solution
was simultaneously dispensed into the SOR 3225 reactor to engage
the reactants. The syringe containing 2 was protected from light by
covering it with aluminum foil. The reactions were run at
25.degree. C., 50.degree. C. and 65.degree. C. at residence times
of 10 sec, 30 sec, 60 sec and 180 sec. The reactions were monitored
by TLC and ESI-MS. Product 3 was collected after evaporation and
washing with cold Et2O. The white solid product was stored in the
dark at 4.degree. C. Any clogged chips or tubing of the setup was
cleaned using THF and EtOH. The subsequent TLC, ESI-MS, MS/MS and
NMR (.sup.1H and .sup.13C) analyses were performed after
purification.
##STR00002##
NMR
.sup.1H NMR (500 MHz, CDCl.sub.3, ppm): .delta..sub.H=4.84 (t,
J=5.85, 1 H), 4.42 (d, J=7.35 Hz, 1 H), 3.62 (t, J=5.60Hz, 2 H),
3.54 (t, J=5.70Hz, 2 H), 3.51-3.45 (m, 1 H), 1.95-1.92 (m, 2 H),
1.72-1.67 (m, 2 H), 1.62-1.58 (m, 1 H), 1.39-1.30 (m, 2 H),
1.19-1.06 (m, 3 H); .sup.13C NMR (500 MHz, CDCl.sub.3, ppm):
.delta..sub.c=157.04, 49.29, 45.25, 42.12, 33.88, 25.57, 24.9
##STR00003##
ESI-MS (m/z): 205/207 (M+H.sup.+), 227/229 (M+Na.sup.+), 408/410
(2M.sup.+).
ESI-MS/MS of m/z 205: 205 (M+H.sup.+), 123
(C.sub.3H.sub.7ClN.sub.2O+H.sup.+), 83 (C.sub.6H.sub.11.sup.+) (80
(C.sub.2H.sub.6ClN.sup.+)
Full ESI-MS scan and MS/MS of commercially available 3 and
synthesized 3 derived from flow under the reaction conditions of
50.degree. C., 1 min are shown in FIG. 8A and FIG. 8B.
DESI-MS Screening.
Preparation of Reaction (Master) Plates and Stamping on DESI-MS
Slides.
Stock solutions of 3 and nitrosation reagents were made at 4
different concentrations (50, 100, 150, 200 mmol) in THF and ACN.
Each reagent solution was also prepared (0.1 M) in eight different
solvents ((EtOAc, THF, DMSO, Toluene, ACN, DCM, EtOH and MeOH). At
first, 20 .mu.L of 3 solution was dispensed into a 384-well master
plate and then the corresponding nitrosation reagents added to the
plate in a stoichiometry 1:1 using a Beckman i7 liquid handling
robot, resulting in a final volume of 40 .mu.L in each well.
Moreover, a master plate was made using only commercially available
3 and lomustine to compare the data. Rhodamine was dissolved in
acetonitrile (0.25 mg/mL) and transferred to a reservoir. A pin
tool fitted with 50 nL pins was used to transfer solutions from the
master plates as well as from the Rhodamine reservoir onto the
DESI-MS substrates. The master plate was pinned three times in
separate locations with reaction mixtures and Rhodamine once,
resulting in 1536 density on the microtiter plate used as the
DESI-MS substrate.
DESI-MS Outline is shown in FIGS. 9-11
Nitrosation of 1-(2-chloroethyl)-3-cyclohexylurea, 3.
Experimentation.
A solution of 3 (245 mmol, 1 equiv) in 98% formic acid was loaded
into a 1 mL Hamilton gas tight glass syringe. NaNO.sub.2 (735 mmol,
3 equiv) solution in MeOH:H.sub.2O (4:1) was separately loaded into
another 1 mL Hamilton gas tight glass syringe and dispensed into
the SOR 3225 reactor to engage the reactants. The reactions were
run at 0.degree. C. at residence times of 30 sec, 1 min, 3 min, 5
min, 8 min, and 10 min. For nitrosation with 5, a solution of 3 in
ACN:EtOH (3.7:1) (200 mmol, 1 equiv) and 5 in ACN (600 mmol, 3
equiv, protected from light by covering the syringe with aluminum
foil) were loaded into two separate 1 mL Hamilton gas tight glass
syringes and dispensed into the SOR 3223 reactor. All the reactions
were monitored at two different temperatures (50.degree. C. and
25.degree. C.) at residence times of 30 sec, 1 min, 3 min, 5 min, 8
min, and 10 min. Reaction progress was monitored by TLC and ESI-MS.
The reaction mixtures were extracted by Et.sub.2O, evaporated, and
dried over anhydrous Na.sub.2SO.sub.4. The crude oily product was
purified by dissolving it in hot petroleum ether, hot filtering the
solution, and evaporating the filtrate to dryness in vaccuo to give
the yellowish solid lomustine that was stored at -20.degree. C.
TLC, ESI-MS, MS/MS, NMR (.sup.1H and .sup.13C), and yield analyses
were performed after purification Three purification methods were
examined to purify the compounds as described in the main
manuscript. The NMR spectra for the different purification methods
are shown here for comparison.
ESI-MS:
##STR00004##
ESI-MS (m/z): 169 (C.sub.9H.sub.17N.sub.2O.sup.+), 100
(C.sub.6H.sub.13N+H.sup.+), 87(C.sub.3H.sub.7N.sub.2O.sup.+), 83
(C.sub.6H.sub.11.sup.+)
ESI-MS/MS of m/z 169: 169 (C.sub.9H.sub.17N.sub.2O.sup.+), 100
(C.sub.6H.sub.13N+H.sup.+), 87(C.sub.3H.sub.7N.sub.2O.sup.+)
Telescopped Synthesis of Lomustine
Reactors.
For scale up and telescoping of the two steps, fluorinated ethylene
propylene (FEP) tubing was used. The outer diameter of the FEP tube
was 1/16 inches and the inner diameter is 0.8 mm. The first reactor
volume was 5 .mu.L and the second reactor volume was 100 .mu.L.
Experimentation.
Cyclohexaneamine, 1 (1 M, 1 equiv) and triethylamine (0.01 M, 0.01
equiv) were prepared in DCM separately. Next, the two separate
solutions were mixed in a 1:1 (v:v) ratio and loaded into a 5 mL
Hamilton gastight syringe. Then, a solution of
1-chloro-2-isocyanatoethane, 2 (0.7 M) was prepared in THF and
loaded into a 5 mL Hamilton gastight syringe that was covered with
aluminum-tape for light protection since it is light sensitive. The
two syringes were connected to a T-connection and outlet of the
T-connector was connected to the first tubing reactor using
micro-tubes, check valves and other connectors (FIG. 17 and FIG.
18). The setup for producing 3 was assembled and placed in a heated
H.sub.2O bath that was maintained at 50.degree. C. The outlet of
the tube-reactor was connected to a four-way connector, where two
of the outlets of the connectors were connected to a 10 mL Hamilton
gastight syringe containing H.sub.2O and a 5 mL Hamilton gastight
syringe containing DCM. The four-way connector provide sufficient
mixing for the extraction of the triethylamine base in the aqueous
phase and leaving 3 in the organic phase. The fourth outlet was
connected to the liquid-liquid separator (SEP-10) in which the DCM
passes through the membrane carrying with it 3 to the next reaction
step. The outlet of the aqueous phase from the separator was
connected to a waste vial. For using sodium nitrite as a
nitrosation reagent, the outlet of the organic phase was connected
to a four-way connector. Sodium nitrite, 4 (1.5 M, 3 equiv)
solution in THF and formic acid were loaded into two separate 5 mL
Hamilton gastight syringes and connected to the a four-way
connector. The outlet of the four-way connector is connected to the
second tubing reactor. When using TBN, 5 as a nitrosation reagent,
we doubled the concentration of the starting material. The outlet
of the organic phase from liquid-liquid extractor was connected to
a T-connector, where one outlet was connected to a 5 mL Hamilton
gastight syringe containing tert-Butyl nitrite, 5 (5 M) in ACN. The
outlet of the T-connector was connected to the second tubing
reactor. The second reactor was placed in a H.sub.2O bath with a
constant temperature of 25.degree. C. and the outlet of this
reactor was connected to a collection vial. The reactions were
monitored by TLC and ESI-MS. The purification and analyses were
conducted as described above, except that HPLC-MS analysis was
performed to evaluate the purity of the product.
TLC and Purification. Reaction progress was monitored by TLC using
1:1 EtOAc:Hexanes as eluent. Lomustine was visualized under
shortwave UV light (230 nm), while 3 was observed after staining
with ninhydrin solution and heating. The extraction and
purification was conducted by taking 500 .mu.L from the collection
vial and washing it with 2 mL of H.sub.2O and 2 mL of Et.sub.2O and
extracted three times. The combined organic layers were dried using
anhydrous NaSO.sub.4. The Et.sub.2O was evaporated and the
yellowish oil/solid was dissolved in hot petroleum ether, hot
filtered, and the filtrate was removed under vacuum. The resulting
solid was recrystallized from petroleum ether.
NMR
.sup.1H NMR (500 MHz, CDCl.sub.3, ppm): .delta..sub.H=6.78 (s, 1H),
4.18 (t, J=7.5, 2 H), 3.92-3.84 (m, 1H), 3.50 (t, J=7.5 Hz, 2 H),
2.07-2.04 (m, 2 H), 1.79-1.75 (m, 2 H), 1.68-1.63 (m, 1 H),
1.45-1.39 (m, 2 H), 1.32-1.24 (m, 3 H); .sup.13C NMR (500 MHz,
CDCl.sub.3, ppm): .delta..sub.C=151.78, 49.98, 40.03, 38.89, 33.09,
25.39, 24.76
Proton NMR of lomustine from flow synthesis, or Carbon NMR of
lomustine, 6 from flow synthesis are available. Comparison of
Proton NMR of lomustine, 6 in flow synthesis with commercially
available lomustine, 6, and comparison of carbon NMR of lomustine,
6 in flow synthesis with commercially available lomustine, 6 are
available upon request.
HPLC/MS-MS Analysis
HPLC/MS analysis was performed on an Agilent 6545 UPLC/quadrupole
time-of-flight (Q-TOF) mass spectrometer (Palo Alto, Calif.), with
an Agilent XDB-C18 column (3.5 .mu.m, 150.times.2.1 mm i.d) and 5
uL injection volume. A binary mobile phase consisting of solvent
systems A and B were used. A was 0.1% formic acid (v/v) in
ddH.sub.2O and B was 0.1% formic acid (v/v) in acetonitrile.
Isocratic elution of A:B at 95:5 was used, with a column flow rate
of 0.3 mL/min. Following the separation, the column effluent was
introduced by positive mode electrospray ionization (ESI) into the
mass spectrometer. High mass accuracy spectra was collected between
70-1000 m/z. Mass accuracy was improved by continuously infusing
Agilent Reference Mass Correction Solution (G1969-85001). ESI
capillary voltage was 3.5 kV, nebulizer gas pressure was 30 psig,
gas temperature was 325.degree. C., drying gas flow rate was 8.0
L/min, fragmentor voltage was 130 V, skimmer was 45 V, and OCT RF V
was 750 V.
Full MS from HPLC-MS/MS and comparison between synthesized
lomustine and commercially available lomustine are available upon
request.
Flow Rates:
Flow Rates for 1.sup.st step Reaction in Labtrix S1 system:
Chemtrix reactor chip: 3225, 10 .mu.L, pressure: ambient
pressure
TABLE-US-00005 R1 R3 Cyclohexane R2 2-Chloroethyl Residence amine,
Triethylamine isocyanate, Time Temperature 1 .mu.L/min .mu.L/min 2
.mu.L/min in min .degree. C. 20 20 20 0.167 50 6.67 6.67 6.67 0.5
50 3.33 3.33 3.33 1 50 1.11 1.11 1.11 3 50 0.67 0.67 0.67 5 50
0.417 0.417 0.417 8 50 0.333 0.333 0.333 10 50
Flow Rates for 2.sup.nd step Reaction using NaNO.sub.2/HCO.sub.2H,
4 in Labtrix S1 system: Chemtrix reactor chip: 3225, 10 .mu.L,
pressure: ambient pressure
TABLE-US-00006 R2 R3 Sodium Formic R1 Nitrite Acid Residence Time 3
.mu.L/min .mu.L/min .mu.L/min in min Temperature .degree. C. 6.67
6.67 6.67 0.5 0 3.33 3.33 3.33 1 0 1.11 1.11 1.11 3 0 0.67 0.67
0.67 5 0 0.417 0.417 0.417 8 0 0.333 0.333 0.333 10 0
Flow Rates for 2.sup.nd step Reaction using TBN, 5 in Labtrix S1
system. Chemtrix reactor chip: 3223, 10 .mu.L, pressure: ambient
pressure
TABLE-US-00007 R2 R1 tert-Butyl nitrite Residence Time 3 .mu.L/min
.mu.L/min in min Temperature .degree. C. 10 10 0.5 50 5 5 1 50 1.67
1.67 3 50 1 1 5 50 0.625 0.625 8 50 0.5 0.5 10 50 10 10 0.5 25 5 5
1 25 1.67 1.67 3 25 1 1 5 25 0.625 0.625 8 25 0.5 0.5 10 25
Telescoped Reaction in Tube:
Nitrosation Reagent: NaNO.sub.2/HCO.sub.2H , 4
TABLE-US-00008 R1 1 + Extraction Triethyl Reactor Extraction step,
R3 R3 amine volume, step, H.sub.2O DCM NaNO.sub.2 HCO.sub.2H
.mu.L/min R2 2 .mu.L/min cm Step 1 .mu.L/min .mu.L/min .mu.L/min
.mu.L/min Step 2 12.56 12.56 Step 1: 5 1 min, 50.24 25.12 25.12
25.12 5 min, Step 2: 50.degree. C. 0.degree. C. 100 12.56 12.56
Step 1: 10 2 min, 50.24 25.12 25.12 25.12 5 min, Step 2: 50.degree.
C. 0.degree. C. 100 12.56 12.56 Step 1: 50 10 min, 50.24 25.12
25.12 25.12 5 min, Step 2: 50.degree. C. 0.degree. C. 100 12.56
12.56 Step 1: 50 10 min, 50.24 25.12 50.24 67.02 3 min, Step 2:
50.degree. C. 0.degree. C. 100
Nitrosation Reagent: TBN , 5
Reactor volume: Step 1=5 cm; Step 2=100 cm
TABLE-US-00009 R1 Extraction 1 + Triethyl Extraction step, R3 amine
step, H.sub.2O DCM TBN .mu.L/min R2 2 .mu.L/min Step 1 .mu.L/min
.mu.L/min .mu.L/min Step 2 12.56 12.56 1 min, 50.degree. C. 50.24
25.12 50.2 5 min, 25/50.degree. C. 12.56 12.56 1 min, 50.degree. C.
50.24 25.12 12.56 8 min, 25.degree. C.
TABLE-US-00010 DESI-MS data of the nitrosation reaction using 4 in
different stoichiometries Normalized Normalized Starting Starting
Product Intensity Intensity Intensity Normalized Inte- nsity no of
Material Material Solvent Stoichiometry m/z (Average) Stdev (max)
(Average- ) Stdev (max) spots, n 3 4 Acetonitrile 150 169.2 213.3
191.6 934.1 0.025 0.030 0.166 144 3 4 Acetonitrile 150 234.7 8.0
6.7 45.1 0.001 0.001 0.007 144 3 4 Acetonitrile 150 239.4 1206.9
1349.7 6575.7 0.069 0.066 0.284 144 3 4 Acetonitrile 150 241.0
390.4 412.9 1980.9 0.022 0.020 0.088 144 3 4 Acetonitrile 150 250.4
143.7 184.3 923.0 0.008 0.005 0.024 144 3 4 Acetonitrile 150 251.2
34.7 40.6 205.3 0.002 0.001 0.006 144 3 4 Acetonitrile 150 337.4
831.0 707.6 4214.5 0.043 0.016 0.100 144 3 4 Acetonitrile 150 373.4
195.1 203.4 1017.1 0.010 0.006 0.026 144 3 4 Acetonitrile 100 169.2
428.3 487.1 3538.6 0.021 0.019 0.124 144 3 4 Acetonitrile 100 234.7
19.3 15.1 80.5 0.002 0.002 0.008 144 3 4 Acetonitrile 100 239.4
2066.8 2519.0 12435.6 0.061 0.049 0.220 144 3 4 Acetonitrile 100
241.0 664.8 776.1 3676.1 0.020 0.015 0.070 144 3 4 Acetonitrile 100
250.4 179.0 200.3 1072.1 0.006 0.003 0.016 144 3 4 Acetonitrile 100
251.2 50.4 57.4 348.6 0.002 0.001 0.005 144 3 4 Acetonitrile 100
337.4 1541.9 1537.4 9588.3 0.050 0.018 0.105 144 3 4 Acetonitrile
100 373.4 261.3 307.9 1751.0 0.008 0.004 0.022 144 3 4 Acetonitrile
50 169.2 53.9 58.1 322.0 0.018 0.019 0.105 144 3 4 Acetonitrile 50
234.7 11.7 16.2 177.5 0.004 0.002 0.015 144 3 4 Acetonitrile 50
239.4 382.9 825.0 5452.0 0.045 0.062 0.326 144 3 4 Acetonitrile 50
241.0 124.8 257.2 1692.1 0.016 0.019 0.101 144 3 4 Acetonitrile 50
250.4 21.3 24.1 145.3 0.005 0.002 0.012 144 3 4 Acetonitrile 50
251.2 6.3 6.7 37.3 0.001 0.001 0.004 144 3 4 Acetonitrile 50 337.4
116.2 130.7 681.0 0.020 0.015 0.075 144 3 4 Acetonitrile 50 373.4
21.0 24.5 133.5 0.004 0.003 0.014 144 3 4 Acetonitrile 200 169.2
134.4 122.3 642.8 0.007 0.002 0.012 144 3 4 Acetonitrile 200 234.7
7.7 8.7 57.9 0.001 0.001 0.003 144 3 4 Acetonitrile 200 239.4
2162.9 2123.7 15812.4 0.119 0.056 0.297 144 3 4 Acetonitrile 200
241.0 608.6 518.4 4106.0 0.035 0.017 0.090 144 3 4 Acetonitrile 200
250.4 39.5 26.3 138.1 0.003 0.001 0.006 144 3 4 Acetonitrile 200
251.2 20.5 49.7 382.9 0.001 0.000 0.002 144 3 4 Acetonitrile 200
337.4 485.0 296.1 1620.7 0.028 0.007 0.042 144 3 4 Acetonitrile 200
373.4 73.1 51.3 324.3 0.004 0.001 0.007 144 3 4 THF 200 169.2
1024.5 744.7 6746.3 0.041 0.059 0.443 144 3 4 THF 200 234.7 30.8
36.3 222.7 0.002 0.001 0.006 144 3 4 THF 200 239.4 1067.2 1527.8
7808.4 0.022 0.034 0.174 144 3 4 THF 200 241.0 333.9 480.7 2373.1
0.007 0.010 0.057 144 3 4 THF 200 250.4 749.2 367.0 2331.3 0.011
0.004 0.022 144 3 4 THF 200 251.2 237.1 227.8 1263.0 0.003 0.002
0.009 144 3 4 THF 200 337.4 13765.9 7680.8 50455.2 0.186 0.054
0.343 144 3 4 THF 200 373.4 1096.5 568.4 3314.2 0.016 0.005 0.038
144 3 4 THF 150 169.2 680.3 705.5 3251.7 0.036 0.033 0.202 144 3 4
THF 150 234.7 43.2 44.1 295.0 0.003 0.001 0.009 144 3 4 THF 150
239.4 1106.3 2107.4 12553.7 0.021 0.031 0.143 144 3 4 THF 150 241.0
366.5 601.2 2985.4 0.008 0.009 0.044 144 3 4 THF 150 250.4 349.0
338.2 1672.1 0.007 0.004 0.020 144 3 4 THF 150 251.2 92.1 92.6
353.0 0.002 0.001 0.008 144 3 4 THF 150 337.4 2590.0 3621.7 15618.2
0.044 0.051 0.185 144 3 4 THF 150 373.4 291.1 374.6 1736.1 0.006
0.006 0.024 144 3 4 THF 100 169.2 1152.9 849.2 4316.7 0.053 0.038
0.236 144 3 4 THF 100 234.7 40.4 42.7 243.0 0.002 0.001 0.014 144 3
4 THF 100 239.4 486.4 1259.8 8600.9 0.008 0.019 0.149 144 3 4 THF
100 241.0 166.2 407.2 2879.3 0.003 0.006 0.044 144 3 4 THF 100
250.4 1070.5 451.4 2449.5 0.013 0.004 0.020 144 3 4 THF 100 251.2
260.9 172.7 1492.2 0.003 0.001 0.011 144 3 4 THF 100 337.4 14213.4
9456.4 39713.7 0.157 0.076 0.339 144 3 4 THF 100 373.4 1262.2 675.0
3233.6 0.016 0.006 0.030 144 3 4 THF 50 169.2 708.7 560.9 3726.2
0.060 0.034 0.211 144 3 4 THF 50 234.7 46.1 56.3 341.8 0.003 0.002
0.020 144 3 4 THF 50 239.4 91.6 164.1 938.4 0.003 0.003 0.023 144 3
4 THF 50 241.0 54.0 70.6 369.5 0.003 0.003 0.015 144 3 4 THF 50
250.4 783.5 422.1 2172.0 0.012 0.003 0.018 144 3 4 THF 50 251.2
227.3 310.1 2172.0 0.003 0.002 0.014 144 3 4 THF 50 337.4 10050.7
9141.9 52775.8 0.125 0.074 0.268 144 3 4 THF 50 373.4 911.9 744.6
4270.9 0.012 0.006 0.022 144 Rhodamine 443.3 12213.1 8739.2 70545.6
0.491 0.101 0.690 384 DESI-MS data of the nitrosation reaction
using 4 as a nitrosation reagent Normalized Normalized Starting
Starting Product Intensity Intensity Intensity Normalized Inten-
sity No of Material Material Solvent m/z (Average) Stdev (max)
(Average) Stdev (max) - spots, n 3 4 Toluene 169.2 2554.4 5564.3
36332.5 0.406 0.173 0.719 144 3 4 Toluene 205.7 7.2 10.4 63.4 0.003
0.003 0.015 144 3 4 Toluene 234.7 2.8 4.5 24.2 0.001 0.001 0.004
144 3 4 Toluene 239.4 2.7 5.8 38.3 0.000 0.001 0.007 144 3 4
Toluene 241.0 2.5 5.8 38.1 0.000 0.001 0.004 144 3 4 Toluene 250.4
1.4 4.4 43.3 0.000 0.001 0.004 144 3 4 Toluene 251.2 30.9 134.5
1279.6 0.002 0.006 0.039 144 3 4 Toluene 337.4 100.7 267.5 1413.6
0.007 0.018 0.146 144 3 4 Toluene 373.4 440.4 1209.9 8746.2 0.026
0.043 0.215 144 3 4 Acetonitrile 169.2 861.8 2266.6 24796.5 0.471
0.136 0.774 144 3 4 Acetonitrile 205.7 6.4 12.7 84.5 0.003 0.004
0.026 144 3 4 Acetonitrile 234.7 0.8 2.0 15.5 0.000 0.001 0.007 144
3 4 Acetonitrile 239.4 1.1 2.4 17.8 0.000 0.000 0.002 144 3 4
Acetonitrile 241.0 6.9 18.6 151.1 0.001 0.002 0.008 144 3 4
Acetonitrile 250.4 5.3 13.5 106.8 0.001 0.002 0.012 144 3 4
Acetonitrile 251.2 330.2 517.7 2676.7 0.039 0.035 0.213 144 3 4
Acetonitrile 337.4 46.4 73.3 493.7 0.005 0.006 0.033 144 3 4
Acetonitrile 373.4 651.5 1237.0 9488.0 0.065 0.035 0.190 144 3 4
DMSO 169.2 4904.5 8789.6 53558.7 0.355 0.137 0.642 144 3 4 DMSO
205.7 25.7 26.7 151.4 0.002 0.002 0.012 144 3 4 DMSO 234.7 1.8 2.3
13.1 0.000 0.001 0.002 144 3 4 DMSO 239.4 17.1 26.6 228.2 0.001
0.000 0.002 144 3 4 DMSO 241.0 5.2 6.1 26.9 0.000 0.000 0.002 144 3
4 DMSO 250.4 1.6 9.6 110.6 0.000 0.000 0.001 144 3 4 DMSO 251.2
101.2 179.2 1054.9 0.002 0.003 0.021 144 3 4 DMSO 337.4 443.8 791.7
4937.7 0.009 0.011 0.053 144 3 4 DMSO 373.4 2602.8 3506.2 30323.8
0.049 0.033 0.232 144 3 4 THF 169.2 1604.6 1828.4 9837.0 0.343
0.165 0.671 144 3 4 THF 205.7 14.3 16.2 107.3 0.002 0.003 0.014 144
3 4 THF 234.7 9.2 20.8 141.7 0.000 0.001 0.003 144 3 4 THF 239.4
68.5 72.4 381.6 0.002 0.002 0.007 144 3 4 THF 241.0 22.7 22.2 99.5
0.001 0.000 0.004 144 3 4 THF 250.4 4.1 7.3 32.2 0.000 0.000 0.001
144 3 4 THF 251.2 254.1 351.0 1963.4 0.008 0.008 0.040 144 3 4 THF
337.4 122.6 116.9 840.1 0.003 0.002 0.019 144 3 4 THF 373.4 3643.6
3629.0 24476.2 0.079 0.036 0.222 144 3 4 Ethanol 169.2 1939.9
2663.0 23988.5 0.315 0.159 0.644 144 3 4 Ethanol 205.7 18.0 22.0
108.9 0.003 0.003 0.017 144 3 4 Ethanol 234.7 9.7 28.9 313.9 0.001
0.001 0.003 144 3 4 Ethanol 239.4 3.1 3.4 20.9 0.000 0.000 0.002
144 3 4 Ethanol 241.0 4.1 3.4 17.3 0.000 0.000 0.003 144 3 4
Ethanol 250.4 3.5 3.4 17.0 0.000 0.000 0.002 144 3 4 Ethanol 251.2
53.0 37.6 152.7 0.002 0.001 0.006 144 3 4 Ethanol 337.4 263.7 193.3
1112.6 0.009 0.005 0.049 144 3 4 Ethanol 373.4 553.9 508.5 2842.8
0.024 0.010 0.074 144 3 4 DCM 169.2 463.4 643.7 3574.7 0.429 0.135
0.733 144 3 4 DCM 205.7 6.8 10.5 72.0 0.005 0.008 0.056 144 3 4 DCM
234.7 1.8 9.0 77.5 0.000 0.001 0.006 144 3 4 DCM 239.4 1.6 3.8 22.9
0.000 0.001 0.005 144 3 4 DCM 241.0 6.9 17.3 111.6 0.001 0.003
0.027 144 3 4 DCM 250.4 4.4 11.7 91.1 0.001 0.002 0.009 144 3 4 DCM
251.2 68.1 211.5 1683.3 0.009 0.014 0.103 144 3 4 DCM 337.4 32.4
77.4 572.0 0.007 0.013 0.060 144 3 4 DCM 373.4 381.0 586.2 3159.2
0.072 0.062 0.206 144 3 4 Ethyl Acetate 169.2 2710.5 3037.9 15437.7
0.325 0.124 0.586 144 3 4 Ethyl Acetate 205.7 23.4 33.0 173.7 0.005
0.006 0.042 144 3 4 Ethyl Acetate 234.7 7.6 29.1 260.3 0.001 0.002
0.017 144 3 4 Ethyl Acetate 239.4 2.0 3.6 16.7 0.000 0.000 0.002
144 3 4 Ethyl Acetate 241.0 4.7 9.6 73.9 0.000 0.000 0.002 144 3 4
Ethyl Acetate 250.4 3.5 7.4 58.3 0.000 0.000 0.002 144 3 4 Ethyl
Acetate 251.2 115.4 304.2 2298.6 0.005 0.009 0.058 144 3 4 Ethyl
Acetate 337.4 34.3 65.0 512.9 0.002 0.002 0.012 144 3 4 Ethyl
Acetate 373.4 2627.7 3123.4 13965.7 0.104 0.081 0.247 144 3 4
Methanol 169.2 1516.5 3046.6 34891.7 0.369 0.172 0.780 144 3 4
Methanol 205.7 15.8 21.8 167.1 0.003 0.004 0.028 144 3 4 Methanol
234.7 1.3 1.6 7.2 0.000 0.001 0.002 144 3 4 Methanol 239.4 1.6 2.1
15.3 0.000 0.000 0.002 144 3 4 Methanol 241.0 2.7 4.0 22.3 0.000
0.000 0.002 144 3 4 Methanol 250.4 1.3 2.3 14.7 0.000 0.000 0.002
144 3 4 Methanol 251.2 19.6 25.3 173.7 0.001 0.001 0.006 144 3 4
Methanol 337.4 288.8 315.4 1590.6 0.013 0.010 0.052 144 3 4
Methanol 373.4 510.8 507.8 2698.7 0.027 0.014 0.072 144 3 443.3
12333.9 13328.7 384.0 0.354 0.083 0.646 384 3 5 Ethyl Acetate 169.2
41.1 47.5 326.1 0.006 0.005 0.028 144 3 5 Ethyl Acetate 205.7 26.2
10.1 59.8 0.004 0.001 0.011 144 3 5 Ethyl Acetate 234.7 46.6 22.4
225.0 0.007 0.002 0.026 144 3 5 Ethyl Acetate 239.4 54.1 121.6
768.5 0.005 0.006 0.027 144 3 5 Ethyl Acetate 241.0 18.6 34.1 215.5
0.002 0.002 0.010 144 3 5 Ethyl Acetate 250.4 243.1 89.4 605.5
0.038 0.008 0.076 144 3 5 Ethyl Acetate 251.2 239.7 89.6 605.5
0.039 0.010 0.112 144 3 5 Ethyl Acetate 337.4 6.5 4.5 38.0 0.001
0.001 0.004 144 3 5 Ethyl Acetate 373.4 19.5 23.7 107.1 0.003 0.004
0.022 144 3 5 Ethanol 169.2 1059.5 1113.0 5710.9 0.047 0.027 0.128
144 3 5 Ethanol 205.7 44.2 47.6 224.7 0.002 0.001 0.006 144 3 5
Ethanol 234.7 22.5 14.2 73.3 0.001 0.000 0.002 144 3 5 Ethanol
239.4 437.1 485.3 2453.7 0.016 0.012 0.091 144 3 5 Ethanol 241.0
155.0 199.6 1496.5 0.005 0.004 0.027 144 3 5 Ethanol 250.4 75.4
57.5 339.3 0.003 0.002 0.009 144 3 5 Ethanol 251.2 33.5 21.6 123.8
0.001 0.000 0.003 144 3 5 Ethanol 337.4 28.4 16.3 85.8 0.001 0.000
0.003 144 3 5 Ethanol 373.4 547.1 727.2 4628.6 0.021 0.014 0.065
144 3 5 THF 169.2 77.4 147.1 824.4 0.008 0.009 0.066 144 3 5 THF
205.7 23.6 18.8 81.5 0.004 0.002 0.009 144 3 5 THF 234.7 55.6 74.9
771.9 0.008 0.004 0.020 144 3 5 THF 239.4 98.5 215.8 1279.6 0.008
0.010 0.046 144 3 5 THF 241.0 31.2 63.7 401.6 0.002 0.003 0.013 144
3 5 THF 250.4 278.7 221.3 1061.8 0.046 0.021 0.088 144 3 5 THF
251.2 285.5 222.9 1061.8 0.048 0.020 0.088 144 3 5 THF 337.4 5.7
5.9 46.3 0.001 0.001 0.007 144 3 5 THF 373.4 23.1 41.3 258.5 0.003
0.004 0.021 144 3 5 DCM 169.2 357.7 408.6 2428.0 0.028 0.018 0.076
144 3 5 DCM 205.7 56.1 22.9 159.1 0.005 0.002 0.011 144 3 5 DCM
234.7 111.7 69.4 561.9 0.010 0.003 0.017 144 3 5 DCM 239.4 255.9
372.5 1692.9 0.019 0.016 0.055 144 3 5 DCM 241.0 76.3 115.2 670.7
0.006 0.005 0.018 144 3 5 DCM 250.4 538.9 212.4 1632.1 0.057 0.017
0.086 144 3 5 DCM 251.2 551.4 202.1 1632.1 0.058 0.015 0.086 144 3
5 DCM 337.4 3.3 3.5 28.0 0.000 0.000 0.002 144 3 5 DCM 373.4 102.8
212.9 2118.2 0.007 0.007 0.038 144 3 5 Toluene 169.2 292.1 271.9
1570.8 0.025 0.016 0.098 144 3 5 Toluene 205.7 25.0 15.0 107.4
0.003 0.001 0.011 144 3 5 Toluene 234.7 37.9 32.5 268.9 0.005 0.001
0.012 144 3 5 Toluene 239.4 179.6 173.3 1095.6 0.012 0.007 0.034
144 3 5 Toluene 241.0 57.9 59.1 394.2 0.004 0.002 0.011 144 3 5
Toluene 250.4 257.8 80.3 515.9 0.040 0.006 0.054 144 3 5 Toluene
251.2 257.5 78.3 463.2 0.040 0.006 0.054 144 3 5 Toluene 337.4 5.5
4.5 24.3 0.001 0.000 0.002 144 3 5 Toluene 373.4 136.8 119.1 632.3
0.012 0.008 0.045 144 3 5 DMSO 169.2 3063.0 4126.1 20263.6 0.192
0.113 0.754 144 3 5 DMSO 205.7 28.5 52.8 347.2 0.003 0.002 0.014
144 3 5 DMSO 234.7 19.5 14.6 117.7 0.004 0.003 0.033 144 3 5 DMSO
239.4 30.2 77.6 745.0 0.002 0.003 0.016 144 3 5 DMSO 241.0 10.1
24.1 233.9 0.001 0.001 0.005 144 3 5 DMSO 250.4 108.8 94.5 872.6
0.020 0.008 0.039 144 3 5 DMSO 251.2 105.8 71.3 325.7 0.022 0.007
0.040 144 3 5 DMSO 337.4 5.5 8.9 57.0 0.001 0.001 0.007 144 3 5
DMSO 373.4 2038.4 3628.2 27327.2 0.095 0.060 0.239 144 3 5 Methanol
169.2 1526.0 1662.0 6465.5 0.070 0.055 0.179 144 3 5 Methanol 205.7
46.2 46.0 249.9 0.002 0.001 0.006 144 3 5 Methanol 234.7 24.3 25.1
113.3 0.001 0.000 0.003 144 3 5 Methanol 239.4 483.9 642.3 3403.1
0.019 0.017 0.090 144 3 5 Methanol 241.0 194.0 382.7 3346.8 0.006
0.006 0.029 144 3 5 Methanol 250.4 71.5 104.6 744.7 0.003 0.002
0.010 144 3 5 Methanol 251.2 43.1 65.4 548.5 0.002 0.001 0.006 144
3 5 Methanol 337.4 26.3 29.5 167.7 0.001 0.001 0.004 144 3 5
Methanol 373.4 1043.9 1687.0 11607.0 0.039 0.035 0.128 144 3 5
Acetonitrile 169.2 3290.0 3100.9 15073.0 0.150 0.056 0.313 144 3 5
Acetonitrile 205.7 33.4 12.5 102.0 0.004 0.001 0.008 144 3 5
Acetonitrile 234.7 57.2 44.7 317.8 0.006 0.002 0.012 144 3 5
Acetonitrile 239.4 187.1 221.0 1440.7 0.008 0.004 0.025 144 3 5
Acetonitrile 241.0 64.9 87.3 669.7 0.003 0.001 0.008 144 3 5
Acetonitrile 250.4 299.6 100.6 629.8 0.038 0.010 0.063 144 3 5
Acetonitrile 251.2 311.5 96.9 629.8 0.040 0.009 0.063 144 3 5
Acetonitrile 337.4 8.2 9.1 50.7 0.000 0.000 0.005 144 3 5
Acetonitrile 373.4 1274.8 1544.7 12113.3 0.049 0.025 0.120 144 3
443.3 40997.0 24891.7 384.0 0.654 0.118 0.807 384
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